I only did a quick google, because I didn't want to run down to my car, but... if what I saw online for 6th level monks is correct, it's not that their blows aren't magical - Empowered Strikes lets the monk choose to do either Force damage or their normal damage type.
Force damage would bypass the whole P/S/B issue
Correction: According to this D&D Beyond article, it's level 5 - https://www.dndbeyond.com/posts/1758-2024-monk-vs-2014-monk-whats-new
Edit: To quote directly from the article: "
Empowered Strike — Level 5
With this new version of Ki-Empowered Strike, you can change the damage type of your Unarmed Strikes to Force damage. Handy for getting around those resistances"
Yes, this is not specific to the Monk though and more monsters are resistant or immune to Force than are resistant to magical bludgeoning, so this is actually a slight nerf.
The issue is more for other martials, especially Rogues and Fighters that have no other damage options. Getting a magic sword used to be the way to bypass this common damage resistance or immunity.
If large numbers of monsters are now resistant or immune to ALL PBS then high level Fighters and Rogues will be MUCH weaker in combat compared to casters then they were under the old rules, despite all the mechanical buffs.